The disclosed embodiments of the present invention relate to video recording, and more particularly, to a video recording method of recording an output video sequence for an image capture module and related video recording apparatus thereof.
Camera modules have become popular elements used in a variety of applications. For example, a smartphone is typically equipped with a camera module, thus allowing a user to easily and conveniently take pictures by using the smartphone. However, due to inherent characteristics of the smartphone, the smartphone is prone to generate blurred images. For example, the camera aperture and/or sensor size of the smartphone is typically small, which leads to a small amount of light arriving at each pixel in camera sensor. As a result, the image quality may suffer from the small camera aperture and/or sensor size.
Besides, due to lightweight and portability of the smartphone, the smartphone tends to be affected by hand shake. Specifically, the shake of the smartphone will last for a period of time. Hence, any picture taken during this period of time would be affected by the hand shake. An image deblurring algorithm may be performed upon the blurred images. However, the computational complexity of the image deblurring algorithm is very high, resulting in considerable power consumption. Besides, artifact will be introduced if the image deblurring algorithm is not perfect.
Moreover, a camera module with an optical image stabilizer (OIS) is expensive. Hence, the conventional smartphone is generally equipped with a digital image stabilizer (i.e., an electronic image stabilizer (EIS)). The digital image stabilizer can counteract the motion of images, but fails to prevent image blurring.
In addition to the camera shake, the movement of a target object within a scene to be captured may cause the captured image to have blurry image contents. For example, considering a case where the user wants to use the smartphone to take a picture of a child, the captured image may have a blurry image content of the child if the child is still when the user is going to touch the shutter/capture button and then suddenly moves when the user actually touches the shutter/capture button.
As a result, when the camera module is affected by hand shake and/or there are moving objects within the scene to be captured, the video recording result would include video frames with bad quality.
Furthermore, it is possible that a target frame rate of an output video sequence is different from a frame rate of an input video sequence. For one example, an input video sequence may be adjusted by dropping video frames with bad quality, which leads to an output video sequence with a lower frame rate. For another example, the camera module may have the image capture capability higher or lower than the image capture capability needed for generating an output video sequence with a desired frame rate. For yet another example, as the camera aperture and/or sensor size of the smartphone is typically small, an extended exposure time may be used for brightness enhancement. As a result, an input video sequence with a lower frame rate is generated correspondingly.
Thus, there is a need for an innovative video recording design which is capable of generating an output video sequence which has a desired frame rate and is composed of video frames with good quality.